AutoLISP实时跟踪鼠标坐标

运用grread函数跟踪鼠标坐标，绘制鼠标轨迹，代码如下。

(defun c:test ()
    (setq p (getpoint))
    (setq n 0)
    (while
    (progn
        (setq input (grread t))
        (cond ((= (car input) 5)
           (setq p1 (cadr input))
           (if (= n 0)
               (command "LINE" p p1 "")
               (command "LINE" "@" p1 "")
           )
           (setq n (1+ n))
           T
          )
          ((= (car input) 3)
           (if (= n 0)
               (command "LINE" p p1 "")
               (command "LINE" "@" p1 "")
           )
           nil
          )
        )
    )
    )
)

代码完。

同时绘制双线并且实现绘制过程的实时预览，这个功能说来容易做起来难。